[JWT4700]

Hey All, 09 328i Xdrive with the N51. i had a few posts in the past about this. the car has finally sat long enough and i plan on starting on replacing the rod bearings. long story short, first engine ate a belt, almost exactly 1 year later it gave up and lost oil pressure completely. had an indy shop put a used engine in it, presumably from a 2011 with 60k miles. noticed an engine rattle a few months late. then lost power brakes. the vacuum pump exploded inside and locked up, even broke the bolt that holds the gear to the front of the pump! i replaced the vacuum pump. still had a rattle. replaced everything known to make a rattle noise on the N51. valvetronic motor, both DISAs, chain tensioner, Vanos Solenoids, and a few other things. finally at the next oil change i found the rattle... extremely high copper. my guess is rod bearings. the rattle is coming from bottom of engine - could never pin point the noise with the stethoscope, didnt like trying to make rattle just to listen. ill attach the oil sample and the vac pump failure.
im a little confused on the actual rod bearings. ISTA/NewTis says to check the stamped codes on the crank to get the bearing color. but RealOEM is showing me a part number for the red and blue 11247628034-Red and 11247628035-blue. when i put those number into FCP it says they dont fit my selected car. it shows they fit most of the 335's but only fit the 328ix from 2013-2016. ECS also says they dont fit and to contact them. searching for "Rod Bearings" on FCP it does bring up BMW Rod Bearing Set - Kolbenschmidt 11247576714. this is a set of 12 matching bearings. can someone help me figure out what bearings i actually need?

on another note, for the project i have that i need the 12 con rod bolts, oil pan bolt set and oil pan gasket. is there anything else i missed?
provided the crank isnt shot i do intend on also doing the oil pump, along with the bolts and motor mounts.
I did put an oil pressure gauge on it the other day. 78psi on start up and after about 2 mins it dropped to 48psi. so tit still has descent oil pressure - hopefully its salvageable lol.

sorry for the long post, i do appreciate any help!

[yupetc]

For best results, go with what's said on the crank and go from there. Do check your bearing gap before you finalize the install.

My case may be different, but I've done a full N55 motor rebuild. Initially I bought all the bearing shells corresponding to what the crank tells me, and yeah, FCP and ECTuning did suggest the bearing shells p/n does not match. But N55 is a popular motor to be replacing rod bearings; so it's quite easy to research and confirm fit.

Anyway, be careful, depending on mileage and type of use and abuse the engine has seen, mine was at 186k miles from an F15 X5, when I put the bearings on the plastigauge was showing 0.031" bearing gap on #5 and #6. Ideally, we'd want to be around 0.015"-0.024" (I'm pulling numbers out of my head right now, so I may need to double check what I wrote down.). And BMW usually has it quite tight, I believe they mesh the bearings in at 0.012"-0.016" gap. Note: If at all necessary to up the size of your bearing, BMW color-coded bearing shells has 3 thickness levels. The thickest can never be mixed with the thinnest, so be fully aware of it.

For my case, at that time, instead of upping the bearing shell color, I decided to go for a full N55 build. So bought a new crank and ordered King's performance bearings with Calico Coating for crank and rods. Also did put in CP pistons and Manley rods on same iteration. I don't think you'll go all out on an N51, but mind the bearing gaps and piston ring clearance on your rebuild even when you're using the color-coded bearings. I basically repeatedly check all the clearances and gaps for a month before I finally buttoned everything together.

[JWT4700]

Thanks for the reply!
I did call and talk to fcp and they said the kolbenschmidt bearings will work with out needed the color codes on the crank. I wonder what makes them fit universally? Maybe just not as tight?
The Indy shop that put this engine in said he had trouble getting it started, something with fuel pressure, aside from that I’ve had no issues, it runs good, no codes. Aside from vac pump self destructing the only thing I found wrong with the engine was the crack balancer was shot. My goal is to just get it back on the road… I’d like to get a new engine in the future, rebuild and install it my self, haven’t had any luck with shops doing a good job lately.

[yupetc]

Originally Posted by JWT4700

Thanks for the reply!
I did call and talk to fcp and they said the kolbenschmidt bearings will work with out needed the color codes on the crank. I wonder what makes them fit universally? Maybe just not as tight?
The Indy shop that put this engine in said he had trouble getting it started, something with fuel pressure, aside from that I’ve had no issues, it runs good, no codes. Aside from vac pump self destructing the only thing I found wrong with the engine was the crack balancer was shot. My goal is to just get it back on the road… I’d like to get a new engine in the future, rebuild and install it my self, haven’t had any luck with shops doing a good job lately.

The universal fit bearings will work, you'll just need to double-check your bearing clearances. This is why on my build it took a whole month just to measure those bearing clearances and get everything situated with least amount of variation. The color-coded bearings work well because when the crank is cut from BMW, their QC ended up noting on the crank what corresponding bearing size is to be used, though they don't put the actual journal measurement, we're clued on the color codes (these are measured down to the thousandth of an inch). If you go with an universal set, you'll probably still be fine since the tolerance range is relatively wide enough, so you'll just have measure everything up and seek a combination that offers the least variation in fitment. Plastigauge is a good tool, but it's not as accurate as using a calibrated caliper and micrometer to do the work. Even then, you'll be working with averaged measurements because we're working in teenth and thousandths of an inch here, and it's easy to have the variations.

I did all the work myself unrushed, took me half a year to build my motor. Only spent time on weekends. That way I can trust every step of the way is done in good practice. Shops are there to make money, so they may not take the absolute amount of precaution in doing things. Anyway, I digress, I hope you best luck. Rebuilding an engine can be fun/rewarding, or it could be a full disaster if you don't have the patience and lack the practical experience and technical knowledge. So you'll need a profound assessment prior to committing it. Good luck.

[JWT4700]

Originally Posted by yupetc

The universal fit bearings will work, you'll just need to double-check your bearing clearances. This is why on my build it took a whole month just to measure those bearing clearances and get everything situated with least amount of variation. The color-coded bearings work well because when the crank is cut from BMW, their QC ended up noting on the crank what corresponding bearing size is to be used, though they don't put the actual journal measurement, we're clued on the color codes (these are measured down to the thousandth of an inch). If you go with an universal set, you'll probably still be fine since the tolerance range is relatively wide enough, so you'll just have measure everything up and seek a combination that offers the least variation in fitment. Plastigauge is a good tool, but it's not as accurate as using a calibrated caliper and micrometer to do the work. Even then, you'll be working with averaged measurements because we're working in teenth and thousandths of an inch here, and it's easy to have the variations.

I did all the work myself unrushed, took me half a year to build my motor. Only spent time on weekends. That way I can trust every step of the way is done in good practice. Shops are there to make money, so they may not take the absolute amount of precaution in doing things. Anyway, I digress, I hope you best luck. Rebuilding an engine can be fun/rewarding, or it could be a full disaster if you don't have the patience and lack the practical experience and technical knowledge. So you'll need a profound assessment prior to committing it. Good luck.

I’ve had horrible luck with shops over the years, I have typically always done my own work for the last 15 years, less the jobs that made sense to pay someone else for (torching out exhaust down pipe flange bolts, transmissions lines during winter) I’ve never had the convenience of a garage so my work is done outside, and currently have a gravel driveway lol. I’ve in-framed my DT-466e, pulled the head, dropped the oil pan, pulled the pistons, pulled the cylinder liners, and rebuilt it. So doing this motor isn’t something that scares me. The only downfall to this is I will be doing it with the engine in the car via dropping subframe and the oil pan.

Can you go a bit deeper on how to actually use the plastigauge and the variations you spoke of?
Do you plasticgauge more than one location on the bearing to check for out of round? I do have an expensive caliper and micrometer I can used based on if they fit in there. A full rebuild isn’t an option at the moment but I do plan one in the future. Hoping to get some bearings out it and get hopefully a year out of and in the meantime buy another motor to rebuild so when it’s time I can just pull the old motor and replace it with the rebuilt one.
What should I be looking for on clearance and variation, I’m guessing you mean to use bearings that will yield the clearances all be close to each other?

[yupetc]

Originally Posted by JWT4700

I’ve had horrible luck with shops over the years, I have typically always done my own work for the last 15 years, less the jobs that made sense to pay someone else for (torching out exhaust down pipe flange bolts, transmissions lines during winter) I’ve never had the convenience of a garage so my work is done outside, and currently have a gravel driveway lol. I’ve in-framed my DT-466e, pulled the head, dropped the oil pan, pulled the pistons, pulled the cylinder liners, and rebuilt it. So doing this motor isn’t something that scares me. The only downfall to this is I will be doing it with the engine in the car via dropping subframe and the oil pan.

Can you go a bit deeper on how to actually use the plastigauge and the variations you spoke of?
Do you plasticgauge more than one location on the bearing to check for out of round? I do have an expensive caliper and micrometer I can used based on if they fit in there. A full rebuild isn’t an option at the moment but I do plan one in the future. Hoping to get some bearings out it and get hopefully a year out of and in the meantime buy another motor to rebuild so when it’s time I can just pull the old motor and replace it with the rebuilt one.
What should I be looking for on clearance and variation, I’m guessing you mean to use bearings that will yield the clearances all be close to each other?

Plastiguage only needs to be placed a certain way on the rod journal before you install the rod's big end onto it and tighten it to spec. After that take off the rod and measure how much "mash width" you ended up with, there's a legend to use on the plastigauge's packaging to tell you what gap you'd get.. This is an over-simplified explanation, but it's the best way I can describe it. If you look it up on Youtube, you'll find plenty of people showing how to do it. There aren't that many ways to skin the cat using plastigauge.


If you're doing the job with engine in the bay, I'd reckon you'll also be keeping the rods and pistons in the same cylinder they come from. That's a whole lot different than what I usually work with, so your degree of variation will be much less; whereas in most of my builds, I'd be upgrading the pistons, rods, bearings, sometimes even the crank itself (all of these are new parts).

So you see I have a whole lot more measuring to do to decide what combination of parts to assign to each cylinder. In your case, if you'll ONLY be changing out the rod bearings, then I don't think you'll need to swap the bearing assignments around (assuming the bearing thickness is manufactured to exact specs with almost no variations, and that's possible enough today). But you'll still need to ensure the rod bearing clearance meets the factory spec then you'll be fine. If for some reason your bearing clearance gets too tight, you can find an engine shop to help you cut or grind the journal down to fit. If you have a bearing clearance too loose you can buy bearings that are +.25 and so on. Factory bearing clearances can be found here: https://www.newtis.info/tisv2/a/en/

Your N51 engine should have different specs than the N55 engine I'm so used to. So you'll have to look it up yourself. Best of luck.

[JWT4700]

I finally started on this! I started 2 weeks ago actually. Taking my time working a little bit each weekend. So far so good, pretty simple so far. I dropped the subframe and differential just now. Not sure if I'll drop the pan this week or wait til next weekend, but I shall soon know how bad the bearings are lol.
One problem I did have was with the passenger side cv axle. I REFUSED to come out. I'm not sure what happened exactly. I gave it a few taps and it started to come out, then stopped. After a long time of hammering on it and even air hammering on it it finally came out after about 10 mins of beating on it with a slide hammer. Sadly, it is not salvageable. What does concern me is the clip. It was not on the axle when I pulled it out. It was laying in the tube in the oil pan which I retrieved, but looking at it - I don't think that's all of it. I filtered the diff fluid and it did not come out in the diff fluid either. Any ideas on maybe trying to flush it out of the diff? I don't think it's a very big piece missing but you can see the one side looks to have been cut off as it's angled and not straight.

[Suvorovo]

Sorry about all your problems. Was that an original OEM CV axle? Mine came out quite easily without issue. I've read that cheap after market CV axle have fitment issues. Used a pricey GKN axle, popped in without issue.

[JWT4700]

Originally Posted by Suvorovo

Sorry about all your problems. Was that an original OEM CV axle? Mine came out quite easily without issue. I've read that cheap after market CV axle have fitment issues. Used a pricey GKN axle, popped in without issue.

No it's a cheapo auto parts store brand if I remember correctly. I can't remember why I had to get it at the parts store, that's only ever in an emergency situation I've never had any issues getting them in or out before. This was the first time I've had any issues. I'm not sure why or how it happened.

[JWT4700]

Update…I finally found the source of my rattle!!!! Con rod bearing number 6 has spun! Cap was extremely blue, the bearing itself looks to have spun about 90* as the split between each half inch was looking right at me when I took the cap off lol. The grooves look bad, but I can barely feel them. I saw someone used Emery paper? What should I use to smooth this out? I intend on giving it a good polishing with some type of Emery paper and fitting up the new bearings. I did find some debris in the oil pad and pick up tube, have to see if it’s magnetic or not. I never beat on this engine, not like I ran it very long before hearing the rattle, puzzles me what happened to have it spun a bearing.

[JWT4700]

I got it looking a little better, that’s after a few runs of 320 grit. There’s one groove that seems to only be in the bottom half, I can just barely catch it with my nail, I’m not sure if I’ll be able to get that out or not. I think I’m going to check the clearance on it after work and see what that ends up being.

[JWT4700]

So before I spent hours polishing the crank, I decided I would check the clearances. Looks like it’s within spec at around a .038mm. I’ll continue polishing and see if I can get that scratch out of the center.

[JWT4700]

Almost done putting it all back together, got the subframe back on last night, few more small things to finish up.
Question on oil changes tho…
So the oil pan has a nice thick layer of sludge on it. Spent a long time getting it all cleaned up.
On top of the that, the amount of copper in the oil was insane. Looked like the oil had a good amount of moisture in it as well, probably from sitting so long.
What’s the best way to flush out the old nasty oil, should I try an engine flush or just do a couple oil changes. I would like to get all the old oil flushed out so I have accurate oil samples.
I’ve been using 0w30 for a while now on the e46 and plan to run the same in this. All tho the initial fill will be a mix of 0w40 and 5w30 as I still have some left over and would like to use it for the first fill and maybe change it out after 100 miles.
Any thoughts?

[Phil325i]

Get the engine up to temp. Add this to your oil:

https://www.ebay.co.uk/itm/362507798...Cclp%3A2047675

Run engine for 15 mins at idle, then drain and re-fill with new oil and new filter.

[JWT4700]

Originally Posted by Phil325i

Get the engine up to temp. Add this to your oil:

https://www.ebay.co.uk/itm/362507798...Cclp%3A2047675

Run engine for 15 mins at idle, then drain and re-fill with new oil and new filter.

I was looking at the LuqiMoly engine flush, just didn't know if it was worth it or not. Maybe I'll go with an engine flush. I just want to make sure the old oil and copper out so I have a good baseline oil sample so I can monitor the new bearings, mainly #6 journal that is possible messed up

[JWT4700]

Well I got it all back together yesterday! It was actually pretty easy, I wish I wouldn’t have put it off for so long. I primed the oil system per bmw recommendations while I had an oil pressure gauges hooked up. It was on the 4th crank that it actually got oil pressure to the sensor. It has 80psi oil pressure on start up (seemed a bit high). Seems to run good, took it for maybe a 10 mile test drive. Alignment is scheduled for Tuesday then need to get an inspection then I’ll start driving it more to make sure all is well. It has about 1/4 tank of fuel, which is probably 2 years old lol. I can feel a miss, stumble when going up hills occasionally, but not bad enough to set the CEL - I’m guessing it’s the old fuel that’s in it. Still have a few minor details to finish up, changing the transfer case fluid, rear differential fluid, oil change, and a good interior and exterior cleaning then hopefullly she will be back on the road!

Just for fun I kept track of my hours while doing this, I have about 50 hours of time in it. But I also am very meticulous about my work too, wire wheel every bolt and nut, mating surfaces, etc. it was a fun project, the biggest PITA was the one 10mm bolt that holds the plastic coolant line to the subframe, the 10mm bolt that holds the power steering line bracket to the subframe, conveniently located behind the seat bar, and the power steering banjo bolts on the steering rack were a bit tricky as well. Aside from that it was pretty straight forward.